For a tiny bit of setting reference, the idea of flying Olthoi would likely have never even occurred to anyone prior to now, let alone having heard of such a thing. The overall appearance was quite similar to the Nightmare though.

Well, we saw other kinds of Olthoi in the Facility before the airships exploded. Since they look like big, dangerous bugs, I assumed there could be some Olthoi that could fly. But if they don't even look like it, I guess it could be some sort of armor? o_o

At the very least, I would have expected wings. The blades and spikes suggested that the creature was a metallic construct. In any case, maybe it's just a hopping insect? Fleas can hop around at an insane speed, but often at the expense of directional focus. Obviously an Olthoi would have a lot more control. Or would it...?